Saturday, February 24, 2018

Track, Points and Wiring on the Colliery Branch Module

A couple of weeks since the last update, and another modular section of the layout has track and points permanently down and operational. This section of the layout (represented by the green shaded section of the track diagram) is a corner module made up of two 1200x600mm foam boards, with the resulting L Shape being 1200x1800mm overall (roughly 4x6 feet for the imperialists amongst us).

With each Knauf foam board weighing about 1.15kg, two of these together, with the addition of a light timber frame underneath made up of 38x19mm pine, makes a manageable sized module that is both strong, and with track and wiring is probably around 3.5kg (approx 8 pounds), which is also quite light and easily lifted off the layout framing and onto the mobile tool trolley/workbench in the centre of the room where the majority of work on the module is done.

This particular module contains two main line tracks, as well as the first half of the colliery siding. The main line track closest to the centre is part of the line “into” Gunnedah, and the main line closest to the outside is part of the line “beyond” Gunnedah. As far as the layout is concerned, everything “Beyond Gunnedah” simply wraps around the outside of what is “Towards Gunnedah”. Doing it this way at least gives the impression of distance when operating a train.

Some initial work was done a few months ago when my wife was able to lay out the points and bend some lengths of track relatively accurately to where they were going to go on this module, so it was just a matter of massaging what was already done until it sat exactly where it needed to go.

With the track laid out exactly where it was going to go, the next step is to figure out where the best place to put the dropper wires will be. Using best practices, just about every individual length of track has dropper wires attached, so it is worthwhile thinking about where droppers can go to make connecting them to the main bus wires running underneath the module both as practical and as neat as possible.

Where there are multiple droppers coming through in close proximity, we have twisted pairs of dropper wires together before then soldering them to the main bus wiring. This has no detrimental effect to the power supply to the track, and also reduces the amount of attachment points to the main bus wires.

Once the dropper wires were then soldered to the track and points, the track was then joined together again so that the foam underlay could be measured out and then attached to the track. To assist the foam underlay being bent around a curve, cuts were made most of the way across the foam underlay from the outside edge of the curved section about every inch (25.4mm) or so, allowing the outside edge to fan out as the foam underlay was curved around reducing the tendency for it to buckle up around the inside edge.

Once each section of track was glued to the foam it was then time to glue the track down in position on the module. Before the points are glued into place, holes are cut in the module for the point motors, a very simple task using a “Multitool” ( ) with a cutting blade, which goes through the 50mm thick module foam like a hot knife through butter, and leaves almost zero mess which is a bonus.

Once the track is all glued down into position, holes can be punched through the module foam, which is easily accomplished using a phillips head screwdriver, and the dropper wires can be pushed through. Handy tip, once the hole has been made for the dropper wires, cut a length of plastic drinking straw to the depth of the hole and push the drinking straw section into the hole. Doing this makes pushing the dropper wires through effortless.

Once all of the above board work has been done, the module can be flipped over. track facing down, and the fun can begin with the wiring. I don’t know about anybody else, but I have always found wiring to be quite therapeutic and enjoyable, both the physical aspect of cutting/stripping/crimping/soldering etc, as well as the technical/logical aspect of knowing how it all works. So whilst I am no longer able to do the physical aspect, it is still up to me to work out and then explain where all of the wires go.

Whilst the wiring is pretty much unseen when the module is in position, I still want it to be as neat and tidy as possible. Generally speaking if you take the time to make something look nice, it will typically be a high quality job, and especially so with wiring getting it right the first time is highly desirable, as fault finding can be tedious at best, time consuming, and damn well frustrating.

Like before, taking the time to figure out where the wiring is going to go beforehand makes everything so much simpler. As you can see with the module flipped over, the main bus wiring simply comes in from the front of the module (the plug that joins the bus wiring to the main layout bus wiring yet to be fitted), through the timber frame, and then runs around to where the grouped dropper wires are coming through the  foam module.

 Using a set of wire strippers that allow the plastic insulation to be spread anywhere along the length of wire allows the insulation to be spread where the dropper wires need to be attached, and after soldering the dropper wires in place a small amount of heat shrink is put over the soldered joint.

Once all of the soldering is completed, a few cable ties are used to group the wires together neatly, and we are also trialling a smear of glue along the uncut tag of the cable ties assisted by masking tape, to hold the wiring firmly in place once the module is flipped over into its resting position.

Once the wiring is completed underneath, the module can be flipped over and is ready for final track inspection, and a quick test to make sure that the point motors are operating properly. Although the point motor logic boards are located on the layout proper, it is only a matter of running a couple of wires to the centre of the room where the module is being worked on and connecting them to the point motor  trigger wires (which are also accessible at the front of the module). It is much simpler checking the point motor operation and that the point blades are throwing correctly when you can get your head directly above them, as opposed to when the module is in its location.

Once happy that all track related work is done, the module is then placed back where it belongs and the bus wiring is connected to the main layout bus wiring. If everything has been done correctly the light globe used for short circuit detection for that module will remain unlit, which it did, and upon placing a locomotive on the track and calling up its operating number, it comes to life and happy moves backwards and forwards along the track as it should, which it also did.

Obviously scenery is still to come, but it’s always nice when the track work and wiring is completed for each module, as it is then time to move onto the next module, and get one step closer to being able to run trains around the whole room.


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